Quick Question: NES Stereo Mod / Amplifier

Hey everyone,

First post here, so I hope I'm posting in the right section.

Anyway, I'm gathering parts for some upcoming console mods that I'll likely tackle this winter break.

NES-wise I want to do a stereo mod, but I was also reading that the stereo channels are a bit quiet, which is how I stumbled upon this:



A user on here made 2 of these, 1 for each audio channel, and I'm thinking about doing the same.

Parts-wise I noticed the schematic shows polar capacitors, but I wasn't able to find small rating capacitors that were polar. Is it just the schematic that's showing them polarized, but really it doesn't matter?

A quick picture I found of the NES motherboard makes me think the capacitors used aren't polarized:



I'll probably have more questions, but that's it for now.

Thanks!

Only the 1 and 10µF capacitors are polarized; the --|(-- notation doesn't necessarily imply polarized. (hence the extra +)

There's no particularly good reason to rebuild the entire NES-internal audio chain twice, as opposed to just using an opamp.

I think the notation for a non-polar cap is --||--.

A notation that's usually a non-polar cap is --||--

Only the visible + is a sign of something that's unambiguously polarized. A non-polarized cap can replace a polarized cap of similar ESR.

Thanks everyone! Yeah, I was looking at the --| |-- vs --) |-- notation as well; good tip pointing out that "+" to differentiate between polar and nonpolar.

And yeah, I'm sure the audio could be amplified using another method, but I do like the idea of replicating the original hardware, and I happen to have almost all the parts anyway due to other mods...

If you're removing the CIC at the same time, you could reuse one of the inverters in the 74HCU04 (since the CIC uses four; the audio amplifier here uses one; and the PPU uses one).

I have disabled the lockout chip (not 100% sure if that's the same as the CIC), so that is a thought; good idea!

Yes, the Checking Integrated Circuit is the lockout chip.